5 gallon buckets

Use something long and flat, like a spatula. Maybe even a long thin flathead screwdriver (one that's long enough to reach down), and go all around the circumference of the pot to try to loosen the sides up. Try not to damage any roots.

Then carefully turn the bucket over upside down and while doing that, with the other hand place it around base of the plant (thumb and index, & with other fingers press up against the soil/stem base to brace/cushion as it slides out.

If too hard to turn upside down, try doing it with pot resting sideways and gently try coax it out of pot, but I always prefer gravity if possible. Easier to do when pots are dry (and lighter).

 

... did you wreck the transplant? Lol